Rivet analyses referenceALEPH_2000_I507531Measurement of π0, η, η′, K0S and Λ0 spectra in two and three jet eventsExperiment: ALEPH (LEP) Inspire ID: 507531 Status: VALIDATED Authors:
Beam energies: (45.6, 45.6) GeV Run details:
Measurement of π0, η, η′, K0S and Λ0 spectra in two and three jet events. In addition to the normal inclusive spectra the spectra in individual jets are measured for three jet events. Source code: ALEPH_2000_I507531.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/UnstableParticles.hh"
4#include "Rivet/Projections/FinalState.hh"
5#include "Rivet/Projections/FastJets.hh"
6#include "Rivet/Projections/Beam.hh"
7
8namespace Rivet {
9
10
11 /// @brief pi, eta, eta', K0, lambda spectra
12 class ALEPH_2000_I507531 : public Analysis {
13 public:
14
15 /// Constructor
16 RIVET_DEFAULT_ANALYSIS_CTOR(ALEPH_2000_I507531);
17
18
19 /// @name Analysis methods
20 /// @{
21
22 /// Book histograms and initialise projections before the run
23 void init() {
24
25 // Projections
26 declare(Beam(), "Beams");
27 declare(UnstableParticles(), "UFS");
28 declare(FinalState() , "FS");
29
30 // Histograms
31 // incl
32 book(_h_pi0 , 1,1,1);
33 book(_h_eta , 2,1,1);
34 book(_h_etaP, 3,1,1);
35 book(_h_K0 , 16,1,1);
36 book(_h_lam , 17,1,1);
37 // two jet
38 book(_h_2_pi0 , 4,1,1);
39 book(_h_2_eta , 5,1,1);
40 book(_h_2_etaP, 6,1,1);
41 book(_h_2_K0 , 18,1,1);
42 book(_h_2_lam , 19,1,1);
43 // three jet
44 book(_h_3_pi0 [0], 7,1,1);
45 book(_h_3_pi0 [1], 8,1,1);
46 book(_h_3_pi0 [2], 9,1,1);
47 book(_h_3_eta [0], 10,1,1);
48 book(_h_3_eta [1], 11,1,1);
49 book(_h_3_eta [2], 12,1,1);
50 book(_h_3_etaP[0], 13,1,1);
51 book(_h_3_etaP[1], 14,1,1);
52 book(_h_3_etaP[2], 15,1,1);
53 book(_h_3_K0 [0], 20,1,1);
54 book(_h_3_K0 [1], 21,1,1);
55 book(_h_3_K0 [2], 22,1,1);
56 book(_h_3_lam [0], 23,1,1);
57 book(_h_3_lam [1], 24,1,1);
58 book(_h_3_lam [2], 25,1,1);
59 book(_w2,"/TMP/W2");
60 book(_w3,"/TMP/W3");
61 }
62
63 void findDecayProducts(const Particle & parent, Particles & decay) {
64 for(const Particle & child : parent.children()) {
65 if(child.children().empty()) {
66 decay.push_back(child);
67 }
68 else {
69 findDecayProducts(child,decay);
70 }
71 }
72 }
73
74 /// Perform the per-event analysis
75 void analyze(const Event& event) {
76 // Get beams and average beam momentum
77 const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
78 const double meanBeamMom = ( beams.first.p3().mod() +
79 beams.second.p3().mod() ) / 2.0;
80
81 Particles decay,fs;
82 // unstable particles
83 const UnstableParticles ufs = apply<UnstableParticles>(event, "UFS");
84 for(const Particle & part : ufs.particles(Cuts::pid==111 or Cuts::pid==221 or Cuts::pid==331 or
85 Cuts::pid==310 or Cuts::abspid==3122)) {
86 fs.push_back(part);
87 findDecayProducts(part,decay);
88 }
89 // FS particles
90 for(const Particle & part : apply<FinalState>(event, "FS").particles()) {
91 bool skip=false;
92 for(const Particle & dec :decay) {
93 if(dec.genParticle()==part.genParticle()) {
94 skip=true;
95 break;
96 }
97 }
98 if(skip) continue;
99 fs.push_back(part);
100 }
101 // Definition of the Durham algorithm
102 fastjet::JetDefinition durham_def(fastjet::ee_kt_algorithm, fastjet::E_scheme, fastjet::Best);
103 // pseudojets
104 vector<fastjet::PseudoJet> input_particles;
105 // Pseudo-jets from the non photons
106 unsigned int ix=0;
107 for (const Particle& p : fs ) {
108 const FourMomentum p4 = p.momentum();
109 input_particles.push_back(fastjet::PseudoJet(p4.px(), p4.py(), p4.pz(), p4.E()));
110 input_particles.back().set_user_index(ix);
111 ++ix;
112 }
113 // cluster the jets
114 fastjet::ClusterSequence clust_seq(input_particles, durham_def);
115 PseudoJets jets = fastjet::sorted_by_E(clust_seq.exclusive_jets_ycut(0.01));
116 if(jets.size()==2) _w2->fill();
117 else if(jets.size()==3) _w3->fill();
118 ix=0;
119 for(const Particle & part : fs) {
120 double xE = part.momentum().E()/meanBeamMom;
121 double xP = part.momentum().p3().mod()/meanBeamMom;
122 int ijet = jets.size()!=3 ? -1 : findJet(ix,jets);
123 if(part.pid()==111) {
124 _h_pi0->fill(xE);
125 if(jets.size()==2) {
126 _h_2_pi0->fill(xE);
127 }
128 else if(jets.size()==3) {
129 _h_3_pi0[ijet]->fill(xE);
130 }
131 }
132 else if(part.pid()==221) {
133 _h_eta->fill(xE);
134 if(jets.size()==2) {
135 _h_2_eta->fill(xE);
136 }
137 else if(jets.size()==3) {
138 _h_3_eta[ijet]->fill(xE);
139 }
140 }
141 else if(part.pid()==331) {
142 _h_etaP->fill(xE);
143 if(jets.size()==2) {
144 _h_2_etaP->fill(xE);
145 }
146 else if(jets.size()==3) {
147 _h_3_etaP[ijet]->fill(xE);
148 }
149 }
150 else if(part.pid()==310) {
151 double xi=-log(xP);
152 _h_K0->fill(xi);
153 if(jets.size()==2) {
154 _h_2_K0->fill(xi);
155 }
156 else if(jets.size()==3) {
157 _h_3_K0[ijet]->fill(xi);
158 }
159 }
160 else if(part.abspid()==3122) {
161 double xi=-log(xP);
162 _h_lam->fill(xi);
163 if(jets.size()==2) {
164 _h_2_lam->fill(xi);
165 }
166 else if(jets.size()==3) {
167 _h_3_lam[ijet]->fill(xi);
168 }
169 }
170 else {
171 break;
172 }
173 ix+=1;
174 }
175 }
176
177 int findJet(int id, const PseudoJets & jets) {
178 for(unsigned int ijet=0;ijet<jets.size();++ijet) {
179 for(const PseudoJet & con : jets[ijet].constituents()) {
180 if(con.user_index()==id)
181 return ijet;
182 }
183 }
184 return -1;
185 }
186
187
188 /// Normalise histograms etc., after the run
189 void finalize() {
190 scale(_h_pi0 ,1./sumOfWeights());
191 scale(_h_eta ,1./sumOfWeights());
192 scale(_h_etaP ,1./sumOfWeights());
193 scale(_h_K0 ,1./sumOfWeights());
194 scale(_h_lam ,1./sumOfWeights());
195 scale(_h_2_pi0 ,1./ *_w2);
196 scale(_h_2_eta ,1./ *_w2);
197 scale(_h_2_etaP ,1./ *_w2);
198 scale(_h_2_K0 ,1./ *_w2);
199 scale(_h_2_lam ,1./ *_w2);
200 for(unsigned int ix=0;ix<3;++ix ) {
201 scale(_h_3_pi0[ix] ,1./ *_w3);
202 scale(_h_3_eta[ix] ,1./ *_w3);
203 scale(_h_3_etaP[ix],1./ *_w3);
204 scale(_h_3_K0[ix] ,1./ *_w3);
205 scale(_h_3_lam[ix] ,1./ *_w3);
206 }
207 }
208
209 /// @}
210
211
212 /// @name Histograms
213 /// @{
214 Histo1DPtr _h_pi0 , _h_eta , _h_etaP , _h_K0 , _h_lam ;
215 Histo1DPtr _h_2_pi0 , _h_2_eta , _h_2_etaP , _h_2_K0 , _h_2_lam ;
216 Histo1DPtr _h_3_pi0[3], _h_3_eta[3], _h_3_etaP[3], _h_3_K0[3], _h_3_lam[3];
217 CounterPtr _w2,_w3;
218 /// @}
219
220
221 };
222
223
224 RIVET_DECLARE_PLUGIN(ALEPH_2000_I507531);
225
226
227}
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